Turnstile antena



DeC- 23,y 1941- l G. H. BRowN N 2,267,550

, TURNSTILE ANTENNA Filed Oct. 31, 1940 l@ vm Patented Dec. 23, 1941 UNITED sTATEs PATENT OFFICE y K anverso4 TURNSTILE ANTENA George H. Brown, Haddoniield, N. J., assignor to Radio Corporation of America, a corporation of Delaware Claims.-

`This invention relates to turnstile antennas and especially to a turnstile having a frequency response suitable for wide band transmission of speech, music, or television` signals. Furthermore, the invention relatesto the means for applying simultaneously to a load circuit quadrature phased currents from a pair of adjacent channels, such as sound and picture television signals.

A turnstile antenna is described in United States Patent No. 2,086,976, which was granted on July 13, 1937, to George H. Brown. In the described antenna, four horizontally disposed elements are mounted at 90 intervals on a metal pole. Power gains are obtained by 'stacking several such elementary arrays at half wave intervals. 'I'he 'elements in these stacked arrays ,are arranged in vertical planes pointing, for example, north, east, south and west. ./The ele-f ments in the respective planes are fed in quadrature so that an omnidirectional, horizontally polarized, rotating i'leld is established.

The problem of applying the currents to turnstile antennas involves a knowledge of transmission lines, and matching such lines to the antenna -and to the power source. `While the transmission lines may be designed, adjusted and matched by one skilled in the art, it is diillcult in practice to make such adjustments, if the turnstile is located on the top of a tall mast which represents a hazard to a skilled rigger, not to mention one inexperienced in climbing tall and sometimes poorly protected structures. It is therefore an object of the invention to provide preadjusted means for feeding a turnstile antenna. Another object is to provide a turnstile with means for broadening the frequency. response. Another object is to provide means for applying simultaneously sound and picture representing currents to a turnstile antenna. An additional object is to provide means for establishing I simultaneously horizontally polarized. oppositely rotating omni-directional coaxial fields.

The invention will be described by referring to the accompanying drawing in which Figure 1 is a perspective view of a turnstile antenna;

Figure 2 is an elevational view of a radiator ele- `ment of the instant invention; Figure 3 is a diagram of the transmission line network used in applying currents to one set of turnstile radiators; Figure 4 is a diagram of the transmission line network used in applying simultaneously currents from two sources to the turnstile; and Figure 5 is a diagramof a modified turnstile feeder system.

A wide band response is obtained by using the radiator element of Fig. 2 in place of the conventional rod radiators N, E, S andW of Fig. 1. The radiator element consists of a quarterwave central or inner conductor I which may be welded,

screwed, or otherwise fastened to the mast 3. An outer conductor or sleeve 5 is concentrically arranged with respect to the inner conductor. The outer ends of the inner conductor and sleeve are joined by a short-circuiting plug 1. 'I'he inner end of the sleeve is supported from the inner conductor by an insulated spacer 9. The inner end of the sleeve stops short of the mast so that the sleeve is effectively insulated from the mast for currents applied to its inner end. The concentric line thus formed has a high impedance because it is a quarter wave long. The active portion of the radiatonwhich has a resistance of `35 ohms, is the `outside surface of the sleeve. It is tuned broadly throughout the frequency range of the applied currents.

A plurality of such radiators are substituted for the conductors of the stacked arrays Il, I3. I5, l1, I9 and 2l of the turnstile of Fig. 1. A mast 22 and the radiator elements 23, 25, 21, 23, 3l, 33 in one vertical plane, for example, the plane pointing north, are shown in Fig. 3. It is necessary that these elements be connected so that the applied currents will be co-phased.

This is done by connecting the adjacent pairs' 23--25 by quarter wave concentric lines 35, 31 which are connected together and to a` full wave concentric line 39. The full wave line 39 joins the quarter wave lines 4|, 43 which connect the next pair of radiator elements 2'l-23. The second pair ofquarter wave lines II-43 are also connected to a second full wave line 45. The second full wave line terminates'in a third pair of quarter wave lines 41, I9 which connect the third pair of radiator elements :il- 33. If conventional 70 ohm lines are used, it can be shown that the impedance at the junction point M will be r10/3 ohms. ,It should be understood that the lines may be fed at the junction of the lines 35, 31, 39, where the impedance is also 70/3 ohms, but the symmetrical feed is preferred.

In order that the impedance at the junction point M be made'to match a 70 ohm line 5l, it is necessary to use a coupling device, which is preferably constructed as described in detail in copending application Serial No. 259,069, filed February 28,` 1939, by George H. Brown for Coupling devices. The matching throughout the frequency band may be made by-using two quarter wave lines 53, having characteristic impedances of 30.8 ohms and 53.2 ohms, respectively. These values are selected to provide not only a matching from the 'l0/3 o hm line to the ohm line, but to assure a matching which is substantially independent of the frequency is arranged to feed cophasally the radiator ele--v downwardly extending lines (corresponding to 5|) are of the same length. .j The connections between the terminating of the N, S, E, and W arrays and the power sources are shown in Figui. The terminals A and B of the N and S arrays are connected by a half wave line 51. The terminals C and I2 of the E and W arrays are connected, respectively,

to quarter wave lines 59, 5|,1which are connected' by a half wave line 63. Thus a full wave line is connected between C and D. The terminals B and F are connected by two quarter wave lines 65, 66 whose junctionl H is connected to the trans,

mission line 61 which is connected tothe picture transmitter or other suitable source of power.

Thus connected, the currents applied to the lines N and S will be 180 out of phase. The currents applied to the lines E and W will be 180 out of phase with respect to each other and will be 90 behind the currents applied tothe lines' N and S. Thus, the picture representing currents are applied in quadrature to the transmission lines N, E, S and W and hence to the 'radiator elements pointing north, east, south and west to produce a horizontally polarized iield rotating, fory ex.- ample, in a counter-clockwise,"l direction. The sound transmitter is connected toV the transmission lines by a line 59 which is branched into a three-quarter Wave line 1| and a quarter wave line 13. The three-quarter wave line 1| is connected to the point B at which the transmis'- sion `line from the picture transmitter is con-4 nected to the S line. The quarter wave line 13 is connected to the4 point F a quarter wave below the terminal C, which is also the point at which the picture transmitter line is connected to the line E. 'I'hus connected currents representing the sound signals are applied in phase opposition atv the points B and F, but as previously explained, the phase of the currents at A and B is 180, and the phase of the currents at C and D are 180 apart and 90 behind A and B. In brief, quadrature phase currents are applied to the lines N, E, S and W to produce a horizontally polarized field rotating, for example, in a clockwise direction.

The lengths of the lines 65, 1|, 13 have been chosen so that the lines to the respective power sources each represent high impedances.to the currents from the other source and matched inn,` pedanoes to currents from their own source. That is, line 61 is matched to the picture transmitter; line 69 is matched to the sound transmitter, but lines 65, B6 oilers a high impedance to the currents from the sound transmitter, and lines 1| 13 offer high impedance to currents from the picture transmitter.

'I'he more nearly the frequency of the two carriers, the more perfect will be the rejection of picture carrier by the lines connecting the sound transmitter and vice versa. l.This anomalous situation is the opposite of a conventional filter in which the rejection is usually diminished as the desired and undesired frequencies approach each other. In any event, the desired rejection is obtained by utilizing lines which are quarter wave long or odd integer multiples thereof. Such lines act as impedance inverters and, when their outputs are terminated in low impedances. their inputs oiIer high input impedance. For example, line 61 is a quarter wave removed from B and F; line 69 is a quarter Wave removed from F and three-quarters of a wave from B. Furthermore,

vB isa half wave removed from F by line and a full wave removed by lines 1|, 13; these lines produce no impedance change because they are of half wave length or even integer multiples thereof. However, the fact that lines 1|, 13 are a vhalf wavello'nger than lines t5,` 66 assures opposite rotation'n! the elds.

Instead of lifeeiing the turnstile by the concentric line netwok of Fig. 3 a conventional open line may be 'connected -as shown in Fig. 5, in which case `the arrays pointed north-south and west and east have been separated for convenience. The'radiator elements 'are connected by transposed wires, as described in the aforementioned patent. 'I'he inal elements are connected to terminating concentric lines or transformers 15 which are so designed that they will match the impedances to conventional ohm downwardlyextending transmission lines. These lines N, S, E and W are connected to the transmitters as shown in Fig. 4.

Thus, the invention has been described as an improved turnstile antenna in which the radiator elements are responsive to a band of frequencies.

The radiator elements of each group (one or more groups may be employed) are connected through conventional '10 ohm transmission lines which terminate in a line of 70/3 ohms impedance. This impedance is matched by coupling lines inserted between the 70/3 ohm line and 70 ohm downwardly extending line. Each of the four downwardly extending lines is connected to a transmission line network to derive therefrom currents of quadrature phase. While the transmission line network is described as connected to two transmitters, for example, sound and pictures for television. it should be understood that a single transmitter may be used. When two transmitters are used simultaneously, they are decoupled by a suitable selection `of the transmission line lengths; by rotating the ilelds in opposite Adirections undesired interference is avoided. It should be understood that the transmission line network corresponding to Fig. 4 may be used with any load or antenna system in which the currents from two sources are applied in quadrature phase relation to produce fields rotating in opposite relation. One example of such a system is the antenna disclosed in U. S. Patent No. 2,210,491 which was granted on August 6, 1940, to Robert F. Lewis.

I claim as my invention:

1. A turnstile antenna feeding network including four symmetrically arranged transmission lines, a half wave transmission line connecting two oppositely disposed lines of said four trans- -mission lines, a full wave transmission line connecting the other two of said four transmission lines, a pair of quarter wave lines serially connecting one of the terminal junctions of said half wave line and a point one quarter wave length from one of the terminal junctions of said full wave line, and means for applying currents to the junction oisa-id serially connected quarter wave lines.

2. A turnstile antenna feeding network includ. ing four symmetrically arranged transmission lines, a half wave transmission line connecting two oppositelydisposed lines of said four transmission lines, a full wave transmission line conlines, a three quarters' wave lineand va quarter wave line serially connecting one of the terminal junctions or" said half wave line and a point one quarterwave length from one ofthe terminal junctions of said full wave line, `and `means for `applying currents t'o the junction of said serially wave line serially connecting one o! the terminal junctions of said half wave line and a point'one l'quarter wave length from one of theterminal junctions of said full wave line, means for applying currents to the junction of said serially connected three quarters wave line and said quarter wave line, a pair of quarter wave lines" serially connecting said one terminal junction of said half wave line and said point, and means for applying currents to the junction of said serially connected quarter wave lines.

4. A turnstile antenna including a supporting nectingthe-other two of said four transmission quarters wave line and a quarter wave line seriallyconnecting one of the terminal junctions of said half wave line and a point one quarter wave mast, four radiator velements secured to said mast at 90 intervals to form a coplanar array, four transmission lines of equal length connected respectively to said elements, and means for applying quadrature phased currents to Lvsaid lines, said means including a half wavetransmission line connecting ,two` of said four transmission lines which are connected to oppositely arranged radiators, a full wave transmission line connecting the other two of said four transmission lines, a' pair of quarter wavetransmission lines serially connecting one of the terminal junctions of said half wave line and a point one quarter wave length from one of the terminal junctions of said full line, the junction of said serially connected quarter wave lines forming the input terminals for said antenna.

5. A turnstile antenna includingga supporting mast, four radiator elements secured toA said mast at 90 intervals to forma coplanar array, four transmission lines of equal length connected respectively to said elements, and means for applying quadrature phased currents to said, lines, said means including a half `wave transmission line connecting two of `said `iourtransmission lines which are connected tooppositely arranged radiators, a full wave transmission line connect-. ingthe other two of said four transmission lines,

a three quarters wave line and a quarter wave line serially connecting one of theterminal junctions of said half wave line and a point one quarter wave length from one of the terminal junctions of said full wave line, the junction of said serially connected three quarters wave line and said quarterwave line forming -the input terminals for said antenna. v

6. A turnstile antenna including a supporting mast, four radiator elements secured to said mast at 90 intervals to form a coplanar array, four transmission lines of equal length connected respectively to said elements, means for applying quadrature phased currents to said lines, said l means including a half wave transmission line connecting two of said four transmission lines which are connected to oppositely arranged radiators, a full wave transmission line connecting the other two of said four transmission lines, a three length irom one of the terminal junctions of said full wave line, the junction of said serially connected three quarters wave line and said quarter wave line forming the input terminals for said antenna. and a pairof quarter wave lines serially connecting said terminal junction and said point, the junction of said quarter wave lines forming a second pair of input terminals for said antenna.

7. A turnstile antenna including a supporting mast, a plurality of radiating elements arranged in horizontal planes spaced half a wave length, four radiating elements being disposed at 90 intervals in each of said horizontal planes.- the corresponding elements in each of` said horizontal planes lying in a vertical plane, four symmetrically arranged transmission lines connecting respectively said radiating elements in said vertical planes for applying cophased currents to the elements in` the respective vertical planes, and means for applying quadrature phased currents to said lines, said means including a halt wave transmission line connecting two of said four transmission lines which are connected to oppositelyA arranged radiators, a full wave transmission line connecting the other two of said 8. A turnstile antenna including a supporting i mast, a plurality of radiating elements arranged Y in horizontal planes spaced halt a wave length,

four radiating elements being disposed at 90 intervals in each ofV said horizontal planes, the corresponding elements in each of said horizontal planes lying ina verticalplane, four symmetr rically arranged transmission lines connecting i respectively said radiating elements in said vertical planes for applying cophased currents to the elements in the respective vertical planes, means forapplying quadrature phased currents to said lines, said means including a half wave transmission line connecting twoof said four transmission lines which are connected to oppositely arranged radiators,v a full wave transmission line connecting the other two of said four transmission lines, a three quarters wave `line and a quarter wave line seriallyconnecting one of the terminal junctions of said half wave line and a point one quarter wave length from one of the terminal junctions of said full wave line, the.

junction of said serially connected three quarters wave line and said quarter wave line forming the input terminals for said antenna. i-

9. A turnstile antennaincluding a supporting mast, a plurality of radiating elements arranged in horizontal planes spaced half a wave length,

four radiating elements being disposed at 90 intervals in each of said horizontal planes, ,the corresponding relements in each of said horizontal planes lying in a vertical plane, four symmetrically arranged transmission lines connecting respectively said radiating elements in said vertical planes for applying cophased currents to the elements in the respective vertical planes, means for applying quadrature phased currents to said lines, said means including a half wave transmission line connecting two of said four transmission lines which are connected to oppositely arranged radiators, a full wave transmission line connecting the other two of said four transmission lines, a three quarters wave line and a quarter wave line serially connecting one of the terminal junctions of said half wave line and a point one quarter wave length from one oi.' the terminal junctions of said full wave line, the junction of said serially connected three quarters wave line and said quarter wave line forming the input terminals for said antenna, and a pair of quarter wave lines serially connecting said terminal junction and said point, the junction of said quarter wave lines forming a second pair Kof input terminals for said antenna.

10. A turnstile antenna including in combination a supporting mast, a plurality of radiator elements, each of said elements being broadly responsive to currents covering a band of fre quencies and each including an inner conductor, a concentric conductive sleeve shorter than said inner conductor and surrounding said inner' conductor, means connecting' said inner conductor and said sleeve at their outer ends, said inner conductors being secured to said mast to form va plurality of horizontal arrays of four elements each, said arrays being spaced apart a half wave length, said four elements of each array being respectively located in vertical planes disposed at 90 intervals about said mast, and means for applying quadrature phase currents to said four elements and cophasal currents to the elements of said vertical planes.

11. A turnstile antenna including in combination a supporting mast, a plurality of radiator elements, each of said elements being broadly responsive to currents covering a band of frequencies and each including an inner conductor, a concentric conductive sleeve shorter than said inner conductor and surrounding said inner conductor, means connecting said inner conductor and said sleeve at their outer ends, said inner conductors being secured to said mast to form a plurality of horizontal arrays of four elements each, said arrays being spaced apart a half wave length, said four elements of each array being respectively located in `vertical planes disposed at 90 intervals about said mast, and four transmission lines connected to said four elements respectively to apply quadrature phase currents to said four elements and cophasal currents to the elements of said vertical planes.

12. A turnstile antenna including in combination a supporting mast, a plurality of radiator elements, each of said elements rbeing broadly responsive to currents covering a band of frequencies and each including an inner conductor, a concentric conductive sleeve shorter than said inner conductor and surrounding said inner conductor, means connecting said inner conductor and said sleeve at their outer ends, said inner conductors being secured to said mast to form a plurality of horizontal arrays of four elements each, said arrays being spaced apart a half wave length, said four elements of each array being respectively located in vertical planes disposed at 90 intervals about said mast, the adjacent elements in each of said vertical planes being connected by serially connected quarter wave length lines, full wave length lines connecting the/"junction of said quarter wave lines, and transmission lines for applying currents to said full wave length lines.

13. A turnstile antenna including in combination a supporting mast, a plurality of radiator elements, each of said elements being broadly responsive to currents covering a band of frequencies and each including an inner`conductor, a concentric conductive sleeve shorter than said inner conductor and surrounding said inner conductor, means connecting said inner conductor and said sleeve at their outer ends, said inner conductors being secured to said mast to form a plurality of horizontal arrays of four elements each, said arrays being spaced apart a half wave length, said four elements of each array being respectively located'in vertical planes disposed at intervals about said mast, a plurality of quarter wave lines for serially connecting adjacent radiator elements in each of said vertical planes, aplurality of full wave length lines for connecting the junction of said quarter wave length lines, four transmission lines for applying currents to said full wave lines, and means for coupling said full Wave lines and said four transmission lines to substantially match their impedances and to transfer currents of a wide frequency range without substantial frequency discrimination.

14. An electrical network for feeding from a pair of independent power sources to two pairs of transmission lines ycurrents of quadrature phase including in combination a half wave transmission line connecting two of said pairs of lines, a full wave transmission line connect the other two of said pairs of lines, a three qua -l ters wave line' and a quarter wave line serially connecting one of the terminal junctions oi! said half wave line and a point one quarter wave length from one of the terminal junctions of said full wave line, means connecting one of said sources to the junction of'said serially connected three quarters wave line and said quarter wave line, a pair of quarter wave lines serially connecting said one terminal junction of said half wave line and said point and means connecting the other of said .sources to the junctin of said serially connected quarter wave lines.

15. An electrical network for feeding from two power sources of adjacent channel frequencies to two pairs of transmission lines curren? of quadrature phase including in combinat on a half wave transmission line connecting two of said pairs of lines representing opposite phases, a full wave transmission line connecting the other two of said pairs oi' lines representing opposite phases, a three quarters wave line and a quarter wave line serially connecting one of the terminal junctions of said half wave line and points one quarter Wave length from one of the terminal junctions of said full wave line, means connecting one of said sources to the junction of said serially connected three quarters wave line and said quarter wave line, a pair of quarter wave lines serially connecting said one terminal junction of said half wave line and said points and means connecting the other of said sources to the junction of said serially connected quarter wave lines whereby the currents from each of said sources are applied in quadrature to said four lines but in the sense producing opposite rotations.

GEORGE H. BROWN.

DISCLAIMER 2,267,550.George H. Brown, Haddonield, N. J. TURNBTILE ANTENNA. Patent dated December 23, 1941. Disclaimer filed December 20, 1943, by the assignee, Radio Uorporatz'on of America. Hereby enters this disclaimer to claims 10, 11,` and 12. I [Oficial Gazette January 1x1, 1944.] 

